Patent GB-711245-A (GB)
Title: Improvements in or relating to tire building machines
IPC: B29D30/24
Filed: 1952-01-09
Abstract: 711,245. Tyre-building machines. NATIONAL STANDARD CO. Jan. 9, 1952 [July 20, 1951], No. 685/52. Class 144(1) In a tyre building machine the tyre building drum 98, Figs. 9, 15 has a periphery formed by a plurality of longitudinal staves 175 which are movable radially outwardly by an expanding member 178, to increase the drum diameter, the staves being normally urged radially inwardly and stave setting means 188, 196 independent of the expanding member being provided to arrest the inward movement of the staves in an intermediate expanded position when said expanding member 178 is released to permit inward movement of the staves. The building drum 98 is flanked on each side by' an auxiliary drum 95, 96, Figs. 2 and 3, the surface of which is formed by an expansible bag 115, 116 and a cage 36 is movable axially over the drum assembly. In operation, Figs. 22, 23, with a ply F of carcase fabric wrapped round the drum assembly and bead rings B placed over the ply adjacent the edges of the building drum in its intermediate expanded position, each side of the ply is expanded in turn by the expansible bag 115 or 116 into contact with the cage 36 which is then moved over the building drum to fold the ply about the beads B. The building drum construction allows for initial expansion of the.ply thereon beyond the normal building diameter determined by the intermediate position to stretch the material at the drum edges so that with the drum collapsed to its intermediate or building position the bead rings can be applied firmly against the drum shoulders, Fig. 22a without the use of bead setting rings. Support of drum assembly and cage. The building and auxiliary drums are mounted for rotation on a hollow shaft 2 which is supported in bearings 4, Fig. 4, and 5, Fig. 9,. mounted in the ends of a sleeve 12 supported cantilever fashion in a frame 8 housing a shaft-driving motor 20. The shaft 2 extends beyond the bearing 5, which is sited near the building drum end of the inboard auxiliary drum 95, to within the outboard auxiliary, drum 96. The cage 36 is suspended for axial movement over the drum assembly from a carriage mounted on wheels 35 to run on over-head girders 30 supported above the drum assembly. The carriage is driven by chains 58, 63 from a motor 66 mounted on the frame 8. For control of the sequence of movements of the cage, shown by the arrowed lines in Fig. 24, the dots representing the outboard edge of the cage, limit switches 70a-e are adjustably positioned along a girder 30 for operation by an arm 78 on the carriage, the switches operating in conjunction with one of a bank 68 of push-button controls suspended from the girders 30. In Fig. 24, 'the return movement of the cage over each auxiliary drum after each ply-folding movement is to ensure that the relevant expansible bag 115 or 116 is collapsed on to its drum. Drum assembly. The building drum 98, Fig. 9, is formed in two sections, the inboard section 102 being fixed and keyed to a sleeve 100 keyed to the shaft 2 and the outboard section 104 being keyed to but axially slidable on the sleeye 100. The auxiliary drums 95, 96, Figs. 8, 9, are alike but reversely positioned, each comprising a cylinder 105, 105a having spaced lugs 106 bolted to a flange 108 of the adjacent drum section 102, 104 so that the outboard auxiliary drum 96 is axially movable with the drum section 104. The expansible bags 115, 116 each comprise a wide flat annular tube with a thickened rib portion 118 received in a recess 110 in the relevant cylinder adjacent the building drum. Each bag is provided with four inflating-valve housings 120, Fig. 16, releasably received in the lugs 106 and communicating, via pipes 128, 130, 131 extending through the drums, with a pressure air distributer 138 fitted on the outboard end of the shaft 2. The housings 120 are releasably arranged to avoid damage of the bags 115, 116 in the event of fouling with, and faulty movement of, the cage 36. Building drum. The building drum is in relatively axially movable sections to allow for longitudinal extension of the drum to accommodate tyres of different bead spacing. The periphery staves 175 accordingly are each formed in two parts, a long fixed part 177 and a block 194. Each part 177 has an arcuate peripheral surface, and lateral longitudinal channels 180 which slidably receive guide fingers 200 riveted in channels in the relevant block 194. The outer arcuate surface of each block 194 carries a metal plate 202 which slidably overlaps the surface of the part 177 to lie in a recess 181 thereon. The remote end of each stave part 177, 194 is fixed to a radial pin 183, 195 respectively which passes through the flanged part 108 of the relevant drum sections 102, 104 and is urged inwardly by springs 190, 190a so that its free end rests on a stave-setting ring 188, 196. In the "rest" or collapsed position of the staves, the pins 183, 195 rest on portions 209 of the rings 188, 196 and the inner surfaces of the staves rest on an expansible bag 178 supported on a sleeve 205 extending over the two drum sections 102, 104. Operation of drum assembly. Axial extension of the building drum is effected by manual operation of a ring gear 152, Fig. 8, surrounding the free end of shaft 2, which operates axially fixed draw bolts 155 to move axially a ring 164 to which is attached by rods 166 the movable drum section 104. Fig. 18 shows the building drum in axially extended position. Radial expansion of the building drum is effected by inflation of the bag 178 via pipes 206 extending through the drum to the distributer 138. Initial expansion of the drum lifts the stave pins, against their springs, clear of the stave-setting rings 183, 196. To arrest inward movement of the staves in the intermediate or tyrebuilding position when the bag 178 is deflated, the setting rings 183, 196 are moved axially outwards, by means of fluid-pressure operated pistons 214 working in cylinders 215 disposed in each drum section 102, 104 to bring larger diameter portions 210 below the ends of the stave pins. The outward movement of the pistons 214 is against the action of return springs 216 in the cylinders and is limited by a shoulder on the pistons. Pressure fluid is conducted to the cylinders via pipes 222 from the distributer 138. Fig. 17 shows the building drum in the intermediate expanded position. The various pressure-fluid feeds for the expansible bags 115, 116, 178 and the stave-setting cylinders 215 are led to the distributer 138 through the shaft 2 from a distributer box 25, Fig. 4, on the inboard end of the shaft. The feeds 231-235 to the box 25 are individually controlled by valves 230 which operate under control of push-button switches in the bank 68. Apparatus for applying the fabric plies and the tread may comprise the known applicator which is movable on rails 284 to beneath the drum assembly and comprises a series of belts 285 trained over pulleys 286 carried on arms which are operable to embrace the drum assembly and wrap the stock therearound for splicing. The tread stitching arrangement may comprise the known oppositely moving stitcher wheels 297 and return roller 296. For large building drums an alternative arrangement is described wherein each set of stave pins is urged inwardly by a common spring ring, connecting the ends of the pins, and the stave setting rings are flat discs connected respectively to opposite ends of a common piston and cylinder arrangement. In this arrangement the expansible bag 178 is in two parts, one for each drum section. Specification 683,785 and U.S.A. Specification 2,567,150 are referred to.